Thread-cutter.



0.1 H. TAYLOR. THREAD CUTTER.

APPLICATION FILED ML 91 I916- Patented Aug. 20, 1918.-

2 SHEETS'SHEEI I.

- Charles H .Tavlor 'c.. H. TAYLOR. THREAD CUTTER. APPLICATION FILED MAR. 9, 19 16.

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THREAD-CUTTER.

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Specification'of Letters Patent. 4 1 a;{- -,nt l A g 20 1918 Application filed March 9,1916. Serial No. 83:104.

To all whom it may concern Be it known that I, CHARLES HAvELooK TAYLOR of thecity of Toronto, Province of ()ntario, Dominion of Canada, have invented certain new and useful Improvements in- .hread-Cutters, and the following is a full,

clear, and,eXact description of the same.

My invention relates particularly to automatic machines and has for its object to provide an attachmentfor machines of this type; whereby a thread'may be out either even with the'perimeter of the work orbe hind a shoulder, a feature of the invcn'tion being that the thread may be out before the piece is separated from the stock and the thread commences immediately at the face of the shouldern. Another feature of the invention isthat a thread may be cut on the reduced diameter between the-ends of the bar either to receive a split nut or be subsequently divided and form the screw threaded ends/0f separate pieces. a

Broadly stated, my invention consists of a unitary rotary tool of-circular. form with its perimeter divided'into a plurality of threads each thread-being divided into a plurality 0"5cutting teeth. The number of these outtingxthreads in the embodiment illustrated not an aliquot part of the number of teeth in each thread. The threads are spaced uni-v icrmly around the circumference of the tool," but as the number of threads does not iv'ide the number of teeth in each thread evenlyithe teeth will not be in; lines parallel to. theuaxis of the tool but in oblique lines, the angle of obliquity depending upon the number of teeth in each thread and the lead of the thread. This tool .is, as before men- 7 tioned, rotary, and it is comb1ned'-w1th a chuck, or other stock holding means, also havingrotation imparted to 1t, and the relativeflspeed of the tool and stock is' an important: factor. The stock must be driven at as many times greater speed than the tool as'there arethreads on the tool, the ef- A feet being that one-continuous thread is cut on the'stock equal'in length to the Width of feeding lnechanism by which the stock is intermittently fed throughthe collet, andv a pair of alternating cross slides carrying re spectlvely my improved cutting tool and a cutter 'forseparating' the finished piece from the stock. a

or full comprehension, however, c my invention reference must be had to the ac-.

companying drawingsin which similar reference characters indicate'the same parts,

and wherein, a

Figure 1 is a transverse sectional view of amachine -of the type mentioned and.

equipped with my invention;

igs. 2 and 3 are side elevations of my improved cutter removed; 1

Figs. 4 and 5 are detail views of the thread milling cutter removed and drawn to alarger scale, the cutter being illustrated in process of manufacture with the threads.

formed on the toothed;

6 mrii nber upon which the cutter is mounted;

perimeterv and partially is a sectional View of the annular 7 is an elevation of a portion of a lathe forcarrying my improved attachment and illustrating the attachment in-vertioal section; 4 v i. Fig. 8 is a plan view of the attachment;

Fig. 9 is a diagonal sectional view taken on line 9 9 Fig. 7

Fig. 10 is a diagram-of the gears for ob-,

taining the required relative milling speeds of the cutter and stock; v

Fig. 11 is a detail and elevation of the head'and driving mechanism for, the attachment, and i Fig. 12- is a plan view thereof; The frame of the automatic machine to which my invention is applied is indicated at 2, the cross slides at3, and 4, the-collet at 5, the cams for operating the slides at 6 and 7. and the levers effectingthe operative conand 10 and 11.

My improved thread cutter. has a milling action and it'is incorporated in an attach-- ment mounted upon slide 3 and the cutter by which the finished piece is separated from the stock is carried by an attachment 1 6 mounted rigidly. on a slide 4.

In the present application of my inven nection between'the cams and slides at 9" tion my milling screw cutter consists of an annular member although for other requirements the particular form may be changed, the milling face being the essential feature. This milling face or perimeter is cut to present siX independent and separate threads, 21, 22, 23, 24, 25, and 26 respectively', each thread being cut to present a plurality of teeth as illustrated in Fig. 4. These threads commence at one end or side of the cutter at intervals of one-sixth the circumference and extend parallel around the cutter finishing at the other end or side. They have corresponding leads and each lead is approximity the axial length of the milling face.

a special attachment including the necessary gears and carrying I sponding groove in the cross-slide the annular member which has the milling face above described out upon its perimeter, and I will now describe this attachment. It consists of a pair of frames 30 and 31 which are left and right halves respectively. The left half of the frame has a rib 32 which. engages a correto which it is fastened by bolts or screws. The right half 31, is bolted to and carried by the left half-and between them is mounted an inter nal ear 35, one end of which is ofreduced dia1iieter,3-6, and cut with a left hand thread.

This end of the internal gear has screwed thereon the annular milling cutter, the cutface of which protrudes from the for.

ting ward face 37 of the attachment. This internal gear is driven from a chuck or main driving gear 40 of the machine which. gear is driven in the direction indicated and drives a pinion 41 upon the shaft of which a second pinion 42 is also rigidly mounted. This latter pinion is the driven element with which the driving gear of the attachment come into operative engagement when the cross slide 0 is moved to an operating position. The gears of the attachment consist of the internal gear 35 and a train of gears l3, 4% and 45, the latt'erbeing mountedrigidly upon a I shaft upon which is also rigidly mounted a gear 47 adapted to come into mesh with gear 42 when the slide is shifted to operating position This system of gearing is adapted to impar d-the milling cutter a speed of one revolution to six revolutions of the stock and as it is. animportant factor that these relative speeds be obtained, I will describe the gears specifically in tabulated form:

- Pitch Gear, Teeth. Pitch. diam Out diam.

40-41 7s 20 3,650 3,750 42 21 20 1, 050 1,150 42 20 2,100 2,200 16 14 1,143 v 48 3,249 8:286inside.

As this invention relates only to the millscribed nor illustrated the latter; but it will be understood nevertheless that the stock is advanced as required after each threading and severing operation.

The finished piece is severed from the stock by a cutting tool 50 mountedin a carrier 51 fastened rigidly to the slide 4.

Operation.

In order to produce a double,- triple "or quadruplethread, the driving gearsfshoul'd be changed to run the cutter one-third, a half or two-thirds the number of revolutions of the stock.

The greater number of teeth on the cutter with proportionately less number of revolutions of the cutter, of the three milled, and the fewer the number, th J I'UL ner the edge, while the number of threads govern the speed of both the cut ter and stock which may be varied, to give the proper cutting speed.

From the foregoing it will be seen that my improved milling cutter is essentially of helical form and performs its function without axial movement of either the cutter or the more perfect the edge the stock, and the multiple quality of the cutter may be increased or diminished without departing from the spirit of my invention. I

What I claim is as follows:

1. In a milling screwcutt1ngattachment for an automatic screw machine a frame adapted to be incorporated in the machine,

an internal gear mounted in the frame an annular cutting member mounted upon said gear and means for driving the gear..

2. A milling screw cutter having an even number of toothed helical threads and each thread having an odd number of teeth.

8. A milling screw cutter having an even aliquant part of the number of teeth of each thread.

5. The combination with a screw-cutting machine frame and a rotary stock-holding collet, of a milling screw-cutter having toothed helical multiple threads uniformly spaced around the periphery of the cutter the threads having corresponding number of teeth and the number of threads being an aliquant part of the number of teeth of each thread, and means rotatively connecting the 'collet and cutter whereby the latter is rotated a fraction of the revolutions of the collet equal to number of threads into which the lead of the cutter is divided.

6. A milling screw cutting attachment for an automatic screw machine, comprising a frame adapted to be incorporated in the machine, a gear rotatably mounted in the frame; an annular member rigidly mounted upon the gear and having toothed multiple threads and the number of threads being an aliquant part of the number of teeth of each thread; a driving gear rotatably mounted in the frame; and a train of gears rotatively connecting the driving gear to the internal gear.

7. A "milling screw-cutting attachment for an automatic screw machine, comprising a frame adapted to be incorporated in the machine, a gear rotatably mounted in the frame; a helical milling screw-cutting member rigidly mounted upon the gear; a driving gear rotatably mounted in the frame; and a train of gears rotatively connecting the driving gear to the first mentioned gear.

8. In a screw cutting machine a milling screw-cutter, means for rotating said cutter, and a continuously rotating mechanism for driving said means, such means being normally in operative engagement with said mechanism and adapted to he moved out of engageinent therewith.

9. In a screw-cutting machine, the combination with a rotary stock carrier and a slide, of a milling screw-cutting attachment comprising a frame mounted upon the slide;

an annular member rotatably mounted upon said frame, the perimeter of said member having uniformly circumferentially spaced toothed multiple peripheral threads, means for rotating said annular member, said means including an internal gear, and gears adapted to impart rotation to. the internal gear when the slide is shifted.

10. In a screw-cutting machine, the combination with. a rotary stock carrier, a tooldriving gear in rotative relation therewith, and a pair of cross-slides with means for re ciprocating thesame, of a milling screW- cutting attachment comprising a frame, means fastening the frame'to one of the cross-slides; a cylindrical member rotat ably hearing within the frame and having internal; gear teeth; an annular member mounted rigidly upon one end of the cylindrical member with a portion of its outer perimeter protruding beyond the frame, and the said perimeter having uniformly circumferentially spaced toothed multiple peripheral threads; a driven gear rotatably mounted within the frame and arranged to engage the said tool-driving gear when the slide is shifted in one direction; and a train of gears rotatively connecting the driven gear to the internal gear.

11. In a screw-cutting machine, the combination with a rotary stock-carrier, a tooldriving gear in rotative relation therewith,

and a pair of cross-slides with means for reciprocating the same, of a milling screwcutting attachment comprising a frame, means fastening the frame to one of the cross-slides; a cylindrical member rotatably hearing within the frame and having internal gear teeth; an annular member mounted rigidly upon one end. of the cylindrical member with a portion of its outer perimeter protruding beyond the frame and the said" perimeter having uniformly circumferentially spaced toothed multiple peripheral threads; a driven gear rotatably mounted within the frame and arranged to engage the said tool-driving gear when the slide is shifted. in one direction; a train of gears rotatively connecting the driven gear to the internal gear; and a cutting tool mounted on the other slide and arranged to sever.

In testimony whereof I have signed my name to this specification in the presence of two witnesses.

CHARLES HAVELOCK union. 

